New polyurethane cationomers with naphthyl and phenyltriazene pendants: Synthesis and properties

Two new diols bearing triazene moiety, 1-(alpha-naphthyl)-3,3-di(2-hydroxyethyl) triazene-1 (NT-D) and 1-phenyl-3,3-di(2-hydroxyethyl) triazene-1 (PT-D), were synthesized from aromatic amines and diethanolamine. These monomers were used as chain coextenders in the two-step addition reaction between poly(tetramethylene oxide) diol, 2,4-tolylene diisocyanate, and N-methyldiethanolamine to obtain photosensitive polyurethanes of elastomer type. Triazene polyurethane cationomers with chlorine counterions were prepared via a quaternization reaction of the above polymers with benzyl chloride. All polyurethanes had a quantity of triazene units between 7.02 and 8.93 wt% polymer, and the content of ammonium quaternary groups in the cationic ones was of 30.56 meq/100 g naphthyl triazene polyurethane cationomer (PUC-NT) and 30.19 meq/100 g phenyl triazene polyurethane cationomer (PUC-PT), respectively. Photobehavior of the triazene units in all polymers under continuous Hg-lamp irradiation was similar to that found for monomers, when both chromophores were transformed during UV irradiation. It is concluded that the PT-D acts as a more efficient sensitizer in the UV light-induced reaction but the photolysis in elastomeric films was lower than that observed in solution. The presence of quaternary ammonium structure on the same polymer backbone decreases the constant rates of photolysis. Because the triazene polyurethanes become crosslinked during UV irradiation could be assessed as potential negative-resist polymers. (C) 2004 Wiley Periodicals, Inc.